 /*
  * $Header: /cvshome/build/org.osgi.framework/src/org/osgi/framework/BundlePermission.java,v 1.16 2007/02/20 00:06:02 hargrave Exp $
  *
  * Copyright (c) OSGi Alliance (2004, 2007). All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package org.osgi.framework;

 import java.io.IOException ;
 import java.security.*;
 import java.util.Enumeration ;
 import java.util.Hashtable ;

 /**
  * A bundle's authority to require or provide a bundle or to receive or attach
  * fragments.
  *
  * <p>
  * A bundle symbolic name defines a unique fully qualified name.
  * <p>
  * For example:
  *
  * <pre>
  * <code>
  * org.osgi.example.bundle
  * </code>
  * </pre>
  *
  * <p>
  * <code>BundlePermission</code> has four actions: <code>PROVIDE</code>,
  * <code>REQUIRE</code>,<code>HOST</code>, and <code>FRAGMENT</code>.
  * The <code>PROVIDE</code> action implies the <code>REQUIRE</code> action.
  *
  * @since 1.3
  * @version $Revision: 1.16 $
  */

 public final class BundlePermission extends BasicPermission {

     private static final long serialVersionUID = 3257846601685873716L;

     /**
      * The action string <code>provide</code>.
      */
     public final static String PROVIDE = "provide";

     /**
      * The action string <code>require</code>.
      */
     public final static String REQUIRE = "require";

     /**
      * The action string <code>host</code>.
      */
     public final static String HOST = "host";

     /**
      * The action string <code>fragment</code>.
      */
     public final static String FRAGMENT = "fragment";

     private final static int ACTION_PROVIDE = 0x00000001;
     private final static int ACTION_REQUIRE = 0x00000002;
     private final static int ACTION_HOST = 0x00000004;
     private final static int ACTION_FRAGMENT = 0x00000008;
     private final static int ACTION_ALL = ACTION_PROVIDE
                                                             | ACTION_REQUIRE
                                                             | ACTION_HOST
                                                             | ACTION_FRAGMENT;
     private final static int ACTION_NONE = 0;
     /**
      * The actions mask.
      */
     private transient int action_mask = ACTION_NONE;

     /**
      * The actions in canonical form.
      *
      * @serial
      */
     private String actions = null;

     /**
      * Defines the authority to provide and/or require and or specify a host
      * fragment symbolic name within the OSGi environment.
      * <p>
      * Bundle Permissions are granted over all possible versions of a bundle.
      *
      * A bundle that needs to provide a bundle must have the appropriate
      * <code>BundlePermission</code> for the symbolic name; a bundle that
      * requires a bundle must have the appropriate <code>BundlePermssion</code>
      * for that symbolic name; a bundle that specifies a fragment host must have
      * the appropriate <code>BundlePermission</code> for that symbolic name.
      *
      * @param symbolicName the bundle symbolic name.
      * @param actions <code>PROVIDE</code>,<code>REQUIRE</code>,
      * <code>HOST</code>,<code>FRAGMENT</code> (canonical order).
      */

     public BundlePermission(String symbolicName, String actions) {
         this(symbolicName, getMask(actions));
     }

     /**
      * Bundle private constructor used by BundlePermissionCollection.
      *
      * @param symbolicName the bundle symbolic name
      * @param mask the action mask
      */
     BundlePermission(String symbolicName, int mask) {
         super(symbolicName);
         init(mask);
     }

     /**
      * Called by constructors and when deserialized.
      *
      * @param mask
      */
     private void init(int mask) {
         if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) {
             throw new IllegalArgumentException ("invalid action string");
         }

         action_mask = mask;
     }

     /**
      * Parse action string into action mask.
      *
      * @param actions Action string.
      * @return action mask.
      */
     private static int getMask(String actions) {
         boolean seencomma = false;

         int mask = ACTION_NONE;

         if (actions == null) {
             return (mask);
         }

         char[] a = actions.toCharArray();

         int i = a.length - 1;
         if (i < 0)
             return (mask);

         while (i != -1) {
             char c;

             // skip whitespace
 while ((i != -1)
                     && ((c = a[i]) == ' ' || c == '\r' || c == '\n'
                             || c == '\f' || c == '\t'))
                 i--;

             // check for the known strings
 int matchlen;

             if (i >= 6 && (a[i - 6] == 'p' || a[i - 6] == 'P')
                     && (a[i - 5] == 'r' || a[i - 5] == 'R')
                     && (a[i - 4] == 'o' || a[i - 4] == 'O')
                     && (a[i - 3] == 'v' || a[i - 3] == 'V')
                     && (a[i - 2] == 'i' || a[i - 2] == 'I')
                     && (a[i - 1] == 'd' || a[i - 1] == 'D')
                     && (a[i] == 'e' || a[i] == 'E')) {
                 matchlen = 7;
                 mask |= ACTION_PROVIDE | ACTION_REQUIRE;
             }
             else
                 if (i >= 6 && (a[i - 6] == 'r' || a[i - 6] == 'R')
                         && (a[i - 5] == 'e' || a[i - 5] == 'E')
                         && (a[i - 4] == 'q' || a[i - 4] == 'Q')
                         && (a[i - 3] == 'u' || a[i - 3] == 'U')
                         && (a[i - 2] == 'i' || a[i - 2] == 'I')
                         && (a[i - 1] == 'r' || a[i - 1] == 'R')
                         && (a[i] == 'e' || a[i] == 'E')) {
                     matchlen = 7;
                     mask |= ACTION_REQUIRE;
                 }
                 else
                     if (i >= 3 && (a[i - 3] == 'h' || a[i - 3] == 'H')
                             && (a[i - 2] == 'o' || a[i - 2] == 'O')
                             && (a[i - 1] == 's' || a[i - 1] == 'S')
                             && (a[i] == 't' || a[i] == 'T')) {
                         matchlen = 4;
                         mask |= ACTION_HOST;
                     }
                     else
                         if (i >= 7 && (a[i - 7] == 'f' || a[i - 7] == 'F')
                                 && (a[i - 6] == 'r' || a[i - 6] == 'R')
                                 && (a[i - 5] == 'a' || a[i - 5] == 'A')
                                 && (a[i - 4] == 'g' || a[i - 4] == 'G')
                                 && (a[i - 3] == 'm' || a[i - 3] == 'M')
                                 && (a[i - 2] == 'e' || a[i - 2] == 'E')
                                 && (a[i - 1] == 'n' || a[i - 1] == 'N')
                                 && (a[i] == 't' || a[i] == 'T')) {
                             matchlen = 8;
                             mask |= ACTION_FRAGMENT;
                         }
                         else {
                             // parse error
 throw new IllegalArgumentException (
                                     "invalid permission: " + actions);
                         }

             // make sure we didn't just match the tail of a word
 // like "ackbarfrequire". Also, skip to the comma.
 seencomma = false;
             while (i >= matchlen && !seencomma) {
                 switch (a[i - matchlen]) {
                     case ',' :
                         seencomma = true;
                     /* FALLTHROUGH */
                     case ' ' :
                     case '\r' :
                     case '\n' :
                     case '\f' :
                     case '\t' :
                         break;
                     default :
                         throw new IllegalArgumentException (
                                 "invalid permission: " + actions);
                 }
                 i--;
             }

             // point i at the location of the comma minus one (or -1).
 i -= matchlen;
         }

         if (seencomma) {
             throw new IllegalArgumentException ("invalid permission: " + actions);
         }

         return (mask);
     }

     /**
      * Determines if the specified permission is implied by this object.
      *
      * <p>
      * This method checks that the symbolic name of the target is implied by the
      * symbolic name of this object. The list of <code>BundlePermission</code>
      * actions must either match or allow for the list of the target object to
      * imply the target <code>BundlePermission</code> action.
      * <p>
      * The permission to provide a bundle implies the permission to require the
      * named symbolic name.
      *
      * <pre>
      * x.y.*,&quot;provide&quot; -&gt; x.y.z,&quot;provide&quot; is true
      * *,&quot;require&quot; -&gt; x.y, &quot;require&quot; is true
      * *,&quot;provide&quot; -&gt; x.y, &quot;require&quot; is true
      * x.y,&quot;provide&quot; -&gt; x.y.z, &quot;provide&quot; is false
      * </pre>
      *
      * @param p The target permission to interrogate.
      * @return <code>true</code> if the specified
      * <code>BundlePermission</code> action is implied by this object;
      * <code>false</code> otherwise.
      */

     public boolean implies(Permission p) {
         if (p instanceof BundlePermission) {
             BundlePermission target = (BundlePermission) p;

             return (((action_mask & target.action_mask) == target.action_mask) && super
                     .implies(p));
         }

         return (false);
     }

     /**
      * Returns the canonical string representation of the
      * <code>BundlePermission</code> actions.
      *
      * <p>
      * Always returns present <code>BundlePermission</code> actions in the
      * following order: <code>PROVIDE</code>,<code>REQUIRE</code>,
      * <code>HOST</code>,<code>FRAGMENT.
      * @return Canonical string representation of the <code>BundlePermission</code> actions.
      */

     public String getActions() {
         if (actions == null) {
             StringBuffer sb = new StringBuffer ();
             boolean comma = false;

             if ((action_mask & ACTION_PROVIDE) == ACTION_PROVIDE) {
                 sb.append(PROVIDE);
                 comma = true;
             }

             if ((action_mask & ACTION_REQUIRE) == ACTION_REQUIRE) {
                 if (comma)
                     sb.append(',');
                 sb.append(REQUIRE);
                 comma = true;
             }

             if ((action_mask & ACTION_HOST) == ACTION_HOST) {
                 if (comma)
                     sb.append(',');
                 sb.append(HOST);
                 comma = true;
             }

             if ((action_mask & ACTION_FRAGMENT) == ACTION_FRAGMENT) {
                 if (comma)
                     sb.append(',');
                 sb.append(FRAGMENT);
             }

             actions = sb.toString();
         }

         return (actions);
     }

     /**
      * Returns a new <code>PermissionCollection</code> object suitable for
      * storing <code>BundlePermission</code> objects.
      *
      * @return A new <code>PermissionCollection</code> object.
      */
     public PermissionCollection newPermissionCollection() {
         return (new BundlePermissionCollection());
     }

     /**
      * Determines the equality of two <code>BundlePermission</code> objects.
      *
      * This method checks that specified bundle has the same bundle symbolic
      * name and <code>BundlePermission</code> actions as this
      * <code>BundlePermission</code> object.
      *
      * @param obj The object to test for equality with this
      * <code>BundlePermission</code> object.
      * @return <code>true</code> if <code>obj</code> is a
      * <code>BundlePermission</code>, and has the same bundle
      * symbolic name and actions as this <code>BundlePermission</code>
      * object; <code>false</code> otherwise.
      */
     public boolean equals(Object obj) {
         if (obj == this) {
             return (true);
         }

         if (!(obj instanceof BundlePermission)) {
             return (false);
         }

         BundlePermission p = (BundlePermission) obj;

         return ((action_mask == p.action_mask) && getName().equals(p.getName()));
     }

     /**
      * Returns the hash code value for this object.
      *
      * @return A hash code value for this object.
      */

     public int hashCode() {
         return (getName().hashCode() ^ getActions().hashCode());
     }

     /**
      * Returns the current action mask.
      * <p>
      * Used by the BundlePermissionCollection class.
      *
      * @return Current action mask.
      */
     int getMask() {
         return (action_mask);
     }

     /**
      * WriteObject is called to save the state of the
      * <code>BundlePermission</code> object to a stream. The actions are
      * serialized, and the superclass takes care of the name.
      */

     private synchronized void writeObject(java.io.ObjectOutputStream s)
             throws IOException {
         // Write out the actions. The superclass takes care of the name
 // call getActions to make sure actions field is initialized
 if (actions == null)
             getActions();
         s.defaultWriteObject();
     }

     /**
      * readObject is called to restore the state of the BundlePermission from a
      * stream.
      */
     private synchronized void readObject(java.io.ObjectInputStream s)
             throws IOException , ClassNotFoundException {
         // Read in the action, then initialize the rest
 s.defaultReadObject();
         init(getMask(actions));
     }
 }

 /**
  * Stores a set of <code>BundlePermission</code> permissions.
  *
  * @see java.security.Permission
  * @see java.security.Permissions
  * @see java.security.PermissionCollection
  */

 final class BundlePermissionCollection extends PermissionCollection {

     /**
      * Comment for <code>serialVersionUID</code>
      */
     private static final long serialVersionUID = 3258407326846433079L;

     /**
      * Table of permissions.
      *
      * @serial
      */
     private Hashtable permissions;

     /**
      * Boolean saying if "*" is in the collection.
      *
      * @serial
      */
     private boolean all_allowed;

     /**
      * Create an empty BundlePermissions object.
      *
      */

     public BundlePermissionCollection() {
         permissions = new Hashtable ();
         all_allowed = false;
     }

     /**
      * Adds a permission to the <code>BundlePermission</code> objects. The key
      * for the hash is the symbolic name.
      *
      * @param permission The <code>BundlePermission</code> object to add.
      *
      * @throws IllegalArgumentException If the permission is not a
      * <code>BundlePermission</code> instance.
      * @throws SecurityException If this <code>BundlePermissionCollection</code>
      * object has been marked read-only.
      */

     public void add(Permission permission) {
         if (!(permission instanceof BundlePermission))
             throw new IllegalArgumentException ("invalid permission: "
                     + permission);
         if (isReadOnly())
             throw new SecurityException ("attempt to add a Permission to a "
                     + "readonly PermissionCollection");

         BundlePermission bp = (BundlePermission) permission;
         String name = bp.getName();

         BundlePermission existing = (BundlePermission) permissions.get(name);

         if (existing != null) {
             int oldMask = existing.getMask();
             int newMask = bp.getMask();
             if (oldMask != newMask) {
                 permissions.put(name, new BundlePermission(name, oldMask
                         | newMask));

             }
         }
         else {
             permissions.put(name, permission);
         }

         if (!all_allowed) {
             if (name.equals("*"))
                 all_allowed = true;
         }
     }

     /**
      * Determines if the specified permissions implies the permissions expressed
      * in <code>permission</code>.
      *
      * @param permission The Permission object to compare with this
      * <code>BundlePermission</code> object.
      *
      * @return <code>true</code> if <code>permission</code> is a proper
      * subset of a permission in the set; <code>false</code>
      * otherwise.
      */

     public boolean implies(Permission permission) {
         if (!(permission instanceof BundlePermission))
             return (false);

         BundlePermission bp = (BundlePermission) permission;
         BundlePermission x;

         int desired = bp.getMask();
         int effective = 0;

         // short circuit if the "*" Permission was added
 if (all_allowed) {
             x = (BundlePermission) permissions.get("*");
             if (x != null) {
                 effective |= x.getMask();
                 if ((effective & desired) == desired)
                     return (true);
             }
         }

         // strategy:
 // Check for full match first. Then work our way up the
 // name looking for matches on a.b.*

         String name = bp.getName();

         x = (BundlePermission) permissions.get(name);

         if (x != null) {
             // we have a direct hit!
 effective |= x.getMask();
             if ((effective & desired) == desired)
                 return (true);
         }

         // work our way up the tree...
 int last, offset;

         offset = name.length() - 1;

         while ((last = name.lastIndexOf(".", offset)) != -1) {

             name = name.substring(0, last + 1) + "*";
             x = (BundlePermission) permissions.get(name);

             if (x != null) {
                 effective |= x.getMask();
                 if ((effective & desired) == desired)
                     return (true);
             }
             offset = last - 1;
         }

         // we don't have to check for "*" as it was already checked
 // at the top (all_allowed), so we just return false
 return (false);
     }

     /**
      * Returns an enumeration of all <code>BundlePermission</code> objects in
      * the container.
      *
      * @return Enumeration of all <code>BundlePermission</code> objects.
      */

     public Enumeration elements() {
         return (permissions.elements());
     }
 }

